We describe development of semiconductor scintillators (SCS) on the basis of A II B VI compounds has bridged the gap in a series of "scintillator-photodiode" detectors used in modern multi-channel low-energy devices for visualization of hidden images (tomographs, introscopes). In accordance with the requirements of eventual applications, such SCS materials as ZnSe (Te) show the best matching of intrinsic radiation spectra to photosensitivity spectra of silicon photodiodes (PD) among the materials of similar kind. They are characterized by high radiation and thermal stability of their output parameters, as well as by high conversion efficiency. In this work, a thermodynamic model is described for interaction of isovalent dopants (IVD) with intrinsic point defects of A II B VI semiconductor structures at different ratios of their charges, a decisive role of IVD is shown in formation of the luminescence centers, kinetics of solid-phase reactions and the role of a gas medium are considered under real preparation conditions of ZnSe(Te) scintillation crystals, and luminescence mechanisms in IVD-doped SCS are discussed.